JP2011078070A - Device and method for reading out image - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image reader and a method of reading out an image adapted such that, in the case of disposing a plurality of white LEDs which are point light sources, in a main sweep direction to use as a line light source, by precisely detecting laid-out positions of the LEDs with respect to a manuscript face, it is enabled to light up LEDs only in a portion necessary for a size of the manuscript, so that an electric power consumption is reduced to the minimum. <P>SOLUTION: In an image reader configured to irradiate a manuscript with a plurality of LEDs which are point light sources, disposed in a main sweep direction, the laid-out positions of the LEDs are detected based on positions of forcibly created halations, and, in addition, the size of the manuscript is detected. An LED to light up is selected from the LEDs based on the laid-out positions of the LEDs and the size of the manuscript. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image reading apparatus and an image reading method in which a plurality of white LEDs, which are point light sources, are arranged in the main scanning direction and used as a line light source.

  In recent years, LEDs (Light Emitting Diodes) have been widely used in various fields such as backlights of electronic devices, lighting fixtures, road displays, and the field of image reading devices (scanners) is no exception. In the field of image reading devices, for example, a technique of using a plurality of white LEDs, which are point light sources, in the main scanning direction, as a linear light source similar to a conventional light source (halogen lamp, cold cathode tube, xenon lamp, etc.) It has been known. The use of a conventional light source has a problem that the power consumption when turning on the light source is large, and light is also irradiated to portions other than the set document, which consumes power wastefully. . Therefore, as described above, by adopting the LED instead of the conventional light source, it is possible to obtain merits such as cost reduction when looking at the future, low power consumption, and long life. With the increasing need for environmental protection in recent years, reducing the power consumption of the device has become an indispensable measure for manufacturers, so there is a great merit in adopting LEDs.

  An example of an image reading apparatus using an LED is disclosed in Patent Document 1. The invention of Patent Document 1 aims to prevent leakage of light from outside the document area, reduce power when the light source is turned on, and irradiate the document with uniform light. In order to achieve these objects, the invention of Patent Document 1 controls to illuminate only the document area using a white LED according to the detection result of the document size.

  However, in the invention of Patent Document 1, only the area where the document is placed is provided by providing an auxiliary electrode (auxiliary power supply means) in order to prevent a decrease in the amount of light at the document edge when irradiating only the document region. Is irradiated with uniform light. In other words, although the invention of Patent Document 1 attempts to reduce power consumption by detecting the document size and performing LED lighting control, an auxiliary electrode separate from the LED is provided. The problem of increased consumption remains.

  The present invention has been made in view of the above circumstances, and when a plurality of white LEDs, which are point light sources, are arranged in the main scanning direction to be used as a line light source, the LED mounting position with respect to the document surface is detected systematically. Accordingly, it is an object of the present invention to provide an image reading apparatus and an image reading method in which only a necessary portion of an LED is turned on to reduce power consumption as much as possible.

  In order to achieve such an object, the image reading apparatus of the present invention is based on the position of the halation that is forcibly generated in the image reading apparatus that irradiates a document with a plurality of LEDs that are point light sources arranged in the main scanning direction. An LED mounting position is detected, a document size is detected, and an LED to be lit is selected from the LEDs based on the LED mounting position and the document size.

  The image reading apparatus of the present invention includes an irradiation unit that irradiates a document with a plurality of LEDs that are point light sources arranged in the main scanning direction, a conversion unit that receives reflected light from the document and converts the light into an electrical signal, A halation detecting means for generating halation, a halation detecting means for detecting halation, a document size detecting means for detecting the size of an original, and a control means for controlling an area where an LED is lit. The means detects the LED mounting position with respect to the document based on the halation occurrence position, and the control means determines the area where the LED is lit by comparing the LED mounting position with the document size. It is characterized by.

  The image reading apparatus according to the present invention further includes a reading position detecting unit that detects a reading position of the document for each reading method of the document, and the control unit includes an LED mounting position, a document size, and a document reading position. It is good also as making it controllable the area which lights LED by comparing.

  In the image reading apparatus of the present invention, the control unit may control an area where the LED is lit based on the designated scan area when the user designates the scan area.

  The image reading method of the present invention detects the mounting position of the LED based on the position of the forcibly generated halation in the image reading method in which a plurality of LEDs as point light sources are arranged in the main scanning direction to irradiate the original. The size of the original is detected, and the LED to be lit is selected from the LEDs based on the LED mounting position and the size of the original.

  An image reading method of the present invention includes an irradiation step of irradiating a document with a plurality of LEDs as point light sources arranged in the main scanning direction, a conversion step of receiving reflected light from the document and converting the light into an electrical signal, A halation generation step for generating halation automatically, an LED mounting position detection step for detecting the mounting position of the LED with respect to the document based on the generation position of the halation, a document size detection step for detecting the size of the document, and the LED mounting It has a control step of determining an area where the LED is lit by comparing the position and the size of the document, and controlling the determined area.

  The image reading method of the present invention further includes a reading position detecting step for detecting the reading position of the document for each reading method of the document. In the control step, the LED mounting position, the document size, and the document reading position are included. It is good also as making it controllable the area which lights LED by comparing.

  In the image reading method of the present invention, in the control step, when a scan area is designated by the user, an area where the LED is lit can be controlled based on the designated scan area.

  According to the present invention, the power consumption can be reduced as much as possible by turning on only the necessary LEDs for the document size.

1 is a block diagram illustrating an example of a configuration of an image reading apparatus that is an embodiment of the present invention. 1 is a side view illustrating an example of an appearance of an image reading apparatus according to an embodiment of the present invention. FIG. 3 is a diagram illustrating an internal configuration of a reading module of an image reading apparatus according to an embodiment of the present invention and a positional relationship among a halation generation unit, a reference white plate, and a document reading glass. 1 is a diagram illustrating an optical positional relationship of an image reading apparatus which is an embodiment of the present invention. It is a figure which shows the output distribution for 1 line of CCD output at the time of the reference white board reading of the image reading apparatus which is one Embodiment of this invention. It is a figure which shows the output distribution for 1 line of CCD output at the time of the halation generate | occur | producing at the time of the halation generation part reading of the image reading apparatus which is one Embodiment of this invention. FIG. 3 is a diagram illustrating a positional relationship between an LED mounting position and a document in the image reading apparatus according to the embodiment of the present invention. 6 is a flowchart illustrating an example of an operation when a power source of an image reading apparatus according to an embodiment of the present invention is turned on. 6 is a flowchart illustrating an operation example when the image reading apparatus according to the embodiment of the present invention reads a document. FIG. 5 is a diagram illustrating an image sample when halation occurs in the image reading apparatus according to the embodiment of the present invention. FIG. 5 is a diagram illustrating how the irradiation of a document changes depending on the document in the image reading apparatus according to the embodiment of the present invention. FIG. 3 is a diagram illustrating an example of a configuration of a halation generation unit of an image reading apparatus that is an embodiment of the present invention. FIG. 3 is a diagram illustrating an example of a configuration of a halation generation unit of an image reading apparatus that is an embodiment of the present invention. It is a figure explaining an example when selecting LED which the image reading apparatus which is one Embodiment of this invention lights.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments (embodiments) for carrying out the present invention will be described in detail with reference to the accompanying drawings.

  When an LED is used as the light source in the image reading apparatus, there is a demerit that halation occurs at a position corresponding to the LED mounting pitch and stands out on the image. Basically, it is ideal that the point light source is diffused by the optimal design of the optical system, so that the original is irradiated like a line light source. In other words, it is easy to generate halation itself. It is. Therefore, the image reading apparatus of the present embodiment is provided with means for forcibly generating halation when performing a reading operation as a scanner configuration by arranging a plurality of white LEDs as point light sources in the main scanning direction. It is detected at which position in the main scanning direction the halation occurs. Since the LED mounting position with respect to the document area varies from machine to machine, the image reading apparatus of the present embodiment then accurately grasps the LED mounting position using the detected halation. Then, the image reading apparatus of the present embodiment detects the size of the document set on the document table, and selects the LED to be lit based on the detected size and the grasped LED mounting position. By providing such a feature, the image reading apparatus according to the present embodiment can reduce power consumption as much as possible by turning on only LEDs necessary for the document size.

  FIG. 1 is a block diagram illustrating a configuration example of an image reading apparatus as an embodiment of the present invention.

  A CPU (Central Processing Unit) 1 controls the image reading apparatus of the present embodiment. When the image reading apparatus according to the present embodiment is mounted on an image processing apparatus such as an MFP (Multi Function Peripheral), the CPU 1 may be a CPU that controls the entire image processing apparatus.

  CCD (Charge Coupled Device) / AFE (Analog Front End) control unit 2 has a function of outputting a control signal for driving the CCD16 and AFE8, is controlled by the CPU 1, outputting a group with drive signals to the set To do.

  The flat bed motor control unit 3 has a function of outputting a control signal for driving the motor 6, is controlled by the CPU 1, and outputs a drive signal based on the setting.

  The LED control unit 4 has a function of outputting a control signal for driving the LED 7, is controlled by the CPU 1, and outputs a drive signal based on the setting.

  The drive control unit 5 is an electric module having functions of the CCD / AFE control unit 2, the flat bed motor control unit 3, and the LED control unit 4, and is controlled by the CPU 1.

  The flat bed motor 6 is a motor for driving a reading module to scan a document. Controlled when reading a document placed on a document table.

  The LED 7 is a scanner light source for document irradiation. In the present embodiment, a plurality of light sources are arranged in the main scanning direction so as to have a uniform light amount on the document surface.

  The AFE 8 is an electric module that converts an analog image signal output from the CCD 16 into digital data. The AFE 8 also has a dark offset level adjustment and a bright output adjustment function for the output digital data.

  The halation detector 9 detects the presence or absence of halation from the digital data converted by the AFE 8 when the reflected light from the halation generator 11 is incident on the CCD 16. Further, the halation detection unit 9 detects the positional relationship between a plurality of LED light sources arranged as reading light sources and the pixel position where the output level has locally increased due to halation.

  The image processing unit 10 performs image processing on the scanner digital image data output from the AFE 8. Further, the image processing unit 10 performs processing such as dark output correction, shading correction, and gamma correction, and confirms the image signal level at the halation occurrence position.

  The halation generator 11 forcibly generates halation on the optical path from the LED 7 serving as the light source to the CCD 16. The halation generator 11 has an optical and physical shape in which halation is always generated when the reading module operates this.

  The scanner document size detection unit 12 is a sensor for detecting a document size placed on a document table of the scanner.

  The ADF motor control unit 13 has a function of outputting a control signal for driving the motor 14, is controlled by the CPU 1, and outputs a drive signal based on the setting.

  The ADF motor 14 is a motor that is controlled when a document is conveyed and a reading operation is performed.

  The ADF document size detection unit 15 is a sensor for detecting the document size set on the ADF.

  The CCD 16 is a reading device that converts reflected light from a document into an electrical signal.

  The memory 17 is a memory that temporarily stores various data. The memory 17 also stores information on the halation occurrence position detected by the halation detection unit 9.

  FIG. 2 is a side view showing an example of the appearance of the image reading apparatus according to the present embodiment shown in FIG.

  The scanner unit 21 and the ADF 22 are units that automatically detect the presence / absence of a document and automatically convey the document, and each corresponds to a portion surrounded by a broken line in FIG.

  The document pressure plate 23 is a pressure plate for pressing the document set on the document table.

  The glass table 24 is glass on which a document is placed.

  The reading module 25 is a module on which a CCD 16 as a reading device, an LED 7 as a light source, and the like are mounted. In FIG. 1, it corresponds to a portion surrounded by a broken line in the scanner unit. When reading with a flat bed, the reading module 25 moves in the document area, whereby a reading operation is performed. When reading with the ADF, the reading module 25 moves to the ADF reading position and conveys the document with the ADF, whereby the reading operation is performed.

  FIG. 3 is a diagram illustrating details of the schematic configuration of the image reading apparatus according to the present embodiment illustrated in FIG. 2. FIG. 3 shows the relationship among the internal configuration of the reading module in the image reading apparatus, the halation generator, the reference white plate, the original reading position during flat bed scanning, and the original reading position in the ADF.

  The CCD 30 is a reading device mounted on an SBU (Sensor Board Unit). Reflected light from the document is collected by a lens and imaged on the CCD. The CCD 30 corresponds to the CCD 16 in FIG.

  The lens 31 is a lens for collecting the reflected light from the document.

  The LED substrate 32 is a substrate on which an LED 33 that is a light source for reading is mounted.

  The LEDs 33 are light sources for reading, and a plurality of LEDs 33 are mounted on the LED substrate 32 in the main scanning direction. The LED 33 corresponds to the LED 7 in FIG. The LED drive signal is input to the LED board 32 from the LED control unit 4 of FIG.

  The mirror 34 is a mirror for turning back the reflected light from the document. Although only one is shown in the example of FIG. 3, it is actually composed of a plurality of mirrors.

  SBU 35 is an abbreviation for Sensor Board Unit, and is a reading substrate on which the CCD 30 is mounted.

  The ADF original glass 36 is used when the original is conveyed by the ADF and read. When reading with the ADF, the reading module is moved to the lower part of the glass, and reading is performed by moving the original on the glass.

  The halation generator 37 is a portion that forcibly generates halation when this portion is read with the light source turned on. The halation generator 37 corresponds to the halation generator 11 of FIG. The configuration of the halation generator 37 will be described later with reference to FIGS.

  The reference white plate 38 is a member that serves as a reference for the white level. By reading the reference white plate 38, it is used as data for white level adjustment and shading correction in the AFE 8 of FIG.

  The flat bed original glass 39 is glass for reading a flat bed. When an original is placed on the glass, the reading module moves under the glass and scans the original. The reading module is moved by driving the base motor based on the pulse information output from the flat bed motor control unit 3 of FIG.

  The reading module 40 is a module including a CCD 30, a lens 31, an LED substrate 32, an LED 33 (light source), and a mirror 34.

  FIG. 4 is a diagram for explaining the optical positional relationship of the image reading apparatus. FIG. 4 shows the positional relationship (positional relationship seen from above) between the LED 33 as the light source and the CCD 30 as the reading device.

  As shown in FIG. 4, when the plurality of LEDs 33 mounted on the LED substrate 32 emit light, the light is collected by the lens 31 and imaged by the CCD 30 mounted on the SBU 35.

  FIG. 5 is a diagram showing an output distribution for one line of CCD output at the time of reading a reference white plate. In FIG. 5, the reflected light that is emitted from the LED 33 and illuminates the reference white plate enters the CCD 30, and analog image data output from the CCD is converted into digital data by AFE in one line in the main scanning direction. Distribution is shown.

  Since a plurality of LED 33 as point light sources are arranged and the original is irradiated in a state where the light is optically diffused inside the reading module, substantially uniform light is irradiated on one line of the original surface. As a result, as shown in the graph of FIG. 5, the distribution of the image data becomes uniform. That is, it is difficult to detect the LED mounting position when uniform light is irradiated on the document surface.

  FIG. 6 is a diagram showing an output distribution for one line of CCD output when halation occurs when reading the halation generator. FIG. 6 shows the distribution in the main scanning direction for one line, as in FIG.

  When the halation generator 37 is scanned, uniform light does not enter the CCD 30 and is spaced at intervals of the number of pixels corresponding to the pitch of the plurality of LEDs 33 arranged as in the case of reading the reference white plate shown in FIG. Strong light will enter. Therefore, as shown in the graph of FIG. 6, the analog image data output from the CCD 30 has a high output periodically. Since the halation is forcibly generated by the halation generator 37, the distribution is as shown in the graph of FIG. When the reading module scans the halation generator 37, it is possible to detect the LED mounting position by peak-holding the image level at the position corresponding to the LED pitch. Therefore, this method is adopted in this embodiment.

  FIG. 7 is a diagram showing the positional relationship between the LED mounting position and the document. Hereinafter, a description will be given with reference to FIG.

  In the CCD 30, a CCD effective pixel is started after a fixed pixel (A in the figure) based on a one-line synchronization signal supplied to the CCD 30. The phase is adjusted (registration adjustment) so that the one-line synchronization signal (registration adjustment included) synchronized with this signal becomes the registration position on the original surface. After the fixed pixel (B in the figure) based on this one-line synchronization signal (registration adjustment included) is the registration position (flatbed original reading start position). In the case of flat bed reading, the back side of the original platen is usually the reference position, and in the case of ADF reading, the optical axis center is the reading center position (machine specific). Therefore, the reading position in the main scanning direction is often different between the flat bed and the ADF.

  As described above, the LED mounting position can be detected by detecting the halation occurrence position on the basis of the registration-adjusted one-line synchronization signal as a reference.

  FIG. 14 is a diagram for explaining selection of LEDs to be lit.

  The relationship between the LED mounting position and the resist position is different for each machine. Therefore, it is necessary to change the LED lighting position even if the same document size is detected.

  As shown in FIG. 14, when an end of the document size is detected between LEDn−1 and LEDn, it is necessary to light up to LEDn exceeding the document range. In the case of a system with a wide LED mounting pitch, it may be necessary to light up to LEDn + 1 in some cases. This needs to be optimized for each system in consideration of a decrease in the amount of light at the end.

  FIG. 8 is a flowchart illustrating an operation example when the power supply of the image reading apparatus is turned on.

  When the power of the image reading apparatus is turned on (S60), the CPU 1 turns on all the LEDs 7 (or 33) via the LED control unit 4 (S60).

  The CPU 1 activates the flat bed motor 6 via the flat bed motor control unit 3 and moves the reading module 40 to the halation generation position (the halation generation unit 11 or 37) (S62).

  When the reading module 40 is moved to the halation occurrence position, the CCD 16 updates the peak values of all pixels in the main scanning direction for each line (S63). The peak value is updated until the halation occurrence position is completed (S64 / NO).

  When the reading operation is performed until the halation occurrence position ends (S64 / YES), the halation detection unit 9 detects the halation occurrence position (that is, the LED mounting position) based on the peak value (S65).

  The CPU 1 stores the information of the LED mounting position in the memory 17 based on the one-line synchronization signal (including registration adjustment), and ends (S66). When the power of the image reading apparatus is turned off and on again, the above-described control is performed.

  FIG. 9 is a flowchart illustrating an operation example when the image reading apparatus reads a document.

  The CPU 1 detects that the user starts copying from an operation unit (not shown) mounted on the image reading apparatus, or that a scan is executed as a scanner application from a device (for example, a personal computer) outside the image reading apparatus. (S40 / YES).

  The scanner manuscript size detection unit 12 detects the manuscript size from the information of the manuscript size sensor mounted on the scanner in the case of flatbed reading, and the manuscript size sensor information mounted in the ADF in the case of ADF reading. (S41). Further, when a scan area is designated by the user in the scanner application regardless of the document size, the scanner document size detection unit 12 detects the scan area.

  The CPU 1 selects an LED to be lit during scanning based on the document size or scan area information detected in S41 and the LED mounting position information detected when the power is turned on (S42). Thereafter, the CPU 1 performs LED lighting control based on the selection.

  CPU1 moves the reading module to the lower reference whiteboard (S43), after acquiring the data for shading correction (S44), by scanning the document set on the document or ADF placed on the document glass ( S45), the reading operation is completed.

  FIG. 10 is a diagram showing an image sample when halation actually occurs. As shown in FIG. 10, an image with locally increased light intensity can be confirmed at a position corresponding to the arrangement pitch of the LEDs. The halation is a phenomenon that is easy to check when a book or the like is placed on the original glass and is read from a glass surface that is floating from the glass surface, such as a binding white portion. The reason why this phenomenon occurs is that light reflected by the curved portion of the binding white portion is directly incident on the optical axis of reading as regular reflected light.

  FIG. 11 is a diagram illustrating a state in which document irradiation changes depending on a document.

  As shown in the left diagram of FIG. 11, when a flat original is read, a component (1) that reflects the light applied to the original according to the irradiation angle and a component (2) on the reading optical axis are generated. On the other hand, as shown in the right diagram of FIG. 11, when a three-dimensional original is read, the light irradiated on the original may be input as it is as a strong light as a regular reflection component on the optical axis.

  FIG. 12 is a diagram illustrating an example of the configuration of the halation generator in the present embodiment.

  The halation is a phenomenon that becomes prominent when light from a light source is irradiated on a document and enters the CCD with a strong light intensity due to the effect of regular reflection at that time. Therefore, as shown in FIG. 12, the halation generator 37 has a physical shape curved in the sub-scanning direction, and the reading module 40 scans the halation generator 37. As a result, specularly reflected light is incident on the optical axis at any location in the sub-scanning direction, and halation can be forcibly generated.

  FIG. 13 is a diagram illustrating an example of the configuration of the halation generator in the present embodiment.

  The halation generator 37 shown in FIG. 13 assumes a member having a wide opening angle (mirror or the like) that is curved in the opposite direction to that of FIG. Those having optical characteristics capable of collecting light from all angles are conceivable. It is seen that such mirrors are installed to prevent collisions at the rear-view mirrors installed in the car and in recent years at the corners of roads (called FF mirrors). The reading module 40 scans under the member (halation generator 37) having such optical characteristics. As a result, the specularly reflected light is incident on the optical axis at any location, and it is possible to forcibly generate halation.

  As described above, the image reading apparatus of the present embodiment, first, when performing a read operation as a scanner configured by arranging a plurality of white LED is a point light source in the main scanning direction, forcing means for generating a halation To detect at which position in the main scanning direction the halation occurs. Next, the image reading apparatus of the present embodiment accurately grasps the LED mounting position using the detected halation. Next, the image reading apparatus of the present embodiment detects the size of the document set on the document table, and selects an LED to be lit based on the detected size and the grasped LED mounting position. Accordingly, the image reading apparatus according to the present embodiment can reduce power consumption as much as possible by turning on only LEDs necessary for the document size.

  As mentioned above, although embodiment of this invention was described, it is not limited to the said embodiment, A various deformation | transformation is possible in the range which does not deviate from the summary.

  For example, the operation in the above-described embodiment can be executed by hardware, software, or a combined configuration of both.

  When executing processing by software, a program in which a processing sequence is recorded may be installed and executed in a memory in a computer incorporated in dedicated hardware. Or you may install and run a program in the general purpose computer which can perform various processes.

  For example, the program can be recorded in advance on a hard disk or a ROM (Read Only Memory) as a recording medium. Alternatively, the program, CD-ROM (Compact Disc Read Only Memory), MO (Magneto Optical) disk, DVD (Digital Versatile Disc), a magnetic disk, a removable recording medium such as a semiconductor memory, temporarily, or permanently It can be stored (recorded). Such a removable recording medium can be provided as so-called package software.

  The program may be wirelessly transferred from the download site to the computer in addition to being installed on the computer from the removable recording medium as described above. Or you may wire-transfer to a computer via networks, such as LAN (Local Area Network) and the internet. The computer can receive the transferred program and install it on a recording medium such as a built-in hard disk.

  In addition to being executed in time series in accordance with the processing operations described in the above embodiment, the processing capability of the apparatus that executes the processing, or a configuration to execute in parallel or individually as necessary Is also possible.

1 CPU
2 CCD / AFE control unit 3 Flat bed motor control unit 4 LED board control unit 5 Drive control unit 6 Flat bed motor 7 LED
8 AFE
DESCRIPTION OF SYMBOLS 9 Halation detection part 10 Image processing part 11 Halation generation part 12 Scanner document size detection part 13 ADF motor control part 14 ADF motor 15 ADF document size detection part 16 CCD
17 Memory 21 Scanner unit 22 ADF
23 Original platen 24 Glass stand 25 Reading module 30 CCD
31 Lens 32 LED board 33 LED
34 mirror 35 SBU
36 ADF original glass 37 Halation generating part 38 Reference white plate 39 Flat bed original glass 40 Reading module

JP 2006-115288 A

Claims (8)

In an image reading apparatus that irradiates a document with a plurality of LEDs that are point light sources arranged in the main scanning direction,
Detecting the mounting position of the LED based on the position of forcibly generated halation, and detecting the size of the document;
An image reading apparatus, wherein an LED to be lit is selected from the LEDs based on a mounting position of the LED and a size of the document. Irradiation means for irradiating a document with a plurality of LEDs as point light sources arranged in the main scanning direction;
Conversion means for receiving reflected light from the document and converting the light into an electrical signal;
Halation generating means for forcibly generating halation,
A halation detecting means for detecting the halation;
A document size detecting means for detecting the size of the document;
Control means for controlling an area for lighting the LED,
The halation detection means includes
Based on the occurrence position of the halation, the mounting position of the LED with respect to the document is detected,
The control means includes
An image reading apparatus characterized in that an area for lighting the LED is determined by comparing the mounting position of the LED and the size of the document. Read position detecting means for detecting the read position of the original for each method of reading the original,
The control means includes
3. The image reading according to claim 1, wherein an area where the LED is lit can be controlled by comparing the mounting position of the LED, the size of the original, and the reading position of the original. apparatus. The control means includes
4. The image reading apparatus according to claim 1, wherein when a scan area is designated by a user, an area in which the LED is turned on can be controlled based on the designated scan area. 5. . In an image reading method of irradiating a document by arranging a plurality of LEDs as point light sources in the main scanning direction,
Detecting the mounting position of the LED based on the position of forcibly generated halation, and detecting the size of the document;
An image reading method, wherein an LED to be lit is selected from the LEDs based on a mounting position of the LED and a size of the original. An irradiation step of irradiating a document with a plurality of LEDs as point light sources arranged in the main scanning direction;
A conversion step of receiving reflected light from the document and converting the light into an electrical signal;
A halation generation step for forcibly generating halation;
An LED mounting position detecting step for detecting the mounting position of the LED with respect to the document based on the generation position of the halation;
A document size detecting step for detecting the size of the document;
A control step of determining an area where the LED is lit by comparing the mounting position of the LED and the size of the document, and controlling the determined area;
An image reading method comprising: A reading position detecting step for detecting a reading position of the original for each reading method of the original;
In the control step,
7. The image reading according to claim 5, wherein an area where the LED is lit can be controlled by comparing the mounting position of the LED, the size of the original, and the reading position of the original. Method. In the control step,
8. The image reading method according to claim 5, wherein, when a scan area is designated by a user, an area in which the LED is lit can be controlled based on the designated scan area. 9. .